Area Forecast Discussion
Issued by NWS Mt. Holly, NJ
Issued by NWS Mt. Holly, NJ
Versions:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
046 FXUS61 KPHI 010725 AFDPHI Area Forecast Discussion National Weather Service Mount Holly NJ 325 AM EDT Mon Jul 1 2024 .SYNOPSIS... High pressure builds in later today through Tuesday before moving offshore Wednesday. A surface trough arrives on Thursday as a cold front may approach from the northwest Friday into the weekend. && .NEAR TERM /THROUGH TONIGHT/... A significant air mass change is occurring in the wake of a cold front, therefore it will be much cooler with much lowered dew points/humidity through tonight. Across our lower Delmarva zones to the Cape May County area, a few showers will occur early this morning before much drier air takes over as the cold front settles south and east. The axis of an upper-level trough is forecast to cross our area through about early this afternoon. As this occurs, the center of high pressure across the Great Lakes and upper Ohio Valley gradually builds eastward. This will result in a northerly wind today, and there is a tightened pressure gradient across our area. This is the most pronounced through about early afternoon, therefore with deeper mixing with heating through the morning enhanced some by cold air advection, a notable northerly breeze will be present today. This should start to diminish some by later in the afternoon as the pressure gradient starts to weaken as high pressure draws closer. Given the colder air aloft, cyclonic flow for a while and the passage of the trough axis, some stratocumulus is expected to be around. The forecast soundings show enough moisture at the top of the boundary layer to promote some of these clouds. Given the presence of the trough axis crossing our area through early afternoon, there could be a period of more cloud cover than currently forecast. Some of the stratocumulus is already sliding southward from the Pocono region as it becomes trapped beneath a strengthening subsidence inversion. High temperatures are forecast to be below average for this time of the year, and with dew points down into the 50s and a breeze it will feel significantly cooler today. Any stratocumulus dissipates into this evening as high pressure continues to get closer and even drier air pushes in. The winds are forecast to pretty much decouple in most places during the evening into the overnight. This combined with a clear sky and a much drier air mass will result in lows in the 50s late tonight for much of the region (some lower 60s in the urban centers and along the coast). && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... High pressure will remain the dominant feature through Wednesday. The mostly pleasant and tranquil conditions will continue Tuesday and Wednesday. Highs on Tuesday will be near normal, mainly in the low-mid 80s. However, with dew points forecast to remain in the 50s, another pleasant day looks to be on tap. Lows Tuesday night will be a touch warmer as well, mainly in the low-mid 60s. As the high shifts further east on Wednesday, expect low level southerly return flow to usher in a modest warming trend, but conditions should remain quite pleasant. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... Summary...Approaching trough and cold front will be responsible for rain chances through the long term. Few changes from the previous forecast. Synoptic Overview...A Canadian upper-level trough will push the ridge southward some Thursday and Friday. At the surface, a trough arrives Thursday with a cold front approaching from the northwest Friday. Thursday (Independence Day) through Sunday...Southerly flow becomes more established leading to hot and humid conditions through the weekend. The influence of a Canadian upper-level trough will start to approach during Thursday, however the timing and amplitude of this trough is less certain. As of now, the main trough is more toward the Midwest and therefore the associated cold front may be slow to approach our area late in the week. There may be a pre- frontal trough in our vicinity Thursday into Friday and this may provide enough focus amid a destabilizing air mass to initiate some convection. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Today...VFR. North-northwest winds 10-15 knots with gusts up to 25 knots, diminishing by later this afternoon. Moderate confidence. Tonight...VFR. Northerly winds 5-10 knots, becoming light and variable at many of the terminals. High confidence. Outlook... Tuesday and Wednesday...VFR with no significant weather. Thursday and Friday...Sub-VFR conditions possible with chances (25-35%) for SHRA and TSRA, especially in the afternoon. && .MARINE... A northerly wind will be in place today and with cold air advection occuring within a tightened pressure gradient, mixing is expected to be sufficient for gusts of 25-30 knots. A northerly wind surge is occurring on Delaware Bay early this morning. The winds should lower some this afternoon as the pressure gradient starts to weaken and mixing also decreases. Will maintain the Small Craft Advisory through early this afternoon, otherwise the conditions are anticipated to be below advisory criteria through tonight. Outlook... Tuesday through Friday...Winds and seas are expected to be below SCA criteria. Rip Currents... Today...Northerly winds 15-20 mph with gusts up to 30 mph will gradually diminish some later this afternoon. Due to these elevated winds and breaking waves of 2 to 3 feet, there is a MODERATE risk for the development of dangerous rip currents for the Jersey Shore and the Delaware Beaches. Tuesday...Northeast to east winds near 10 mph with lower breaking waves will result in a LOW risk for the development of dangerous rip currents for the Jersey Shore and the Delaware Beaches. For specific beach forecasts, visit weather.gov/beach/phi && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...Small Craft Advisory until 1 PM EDT this afternoon for ANZ430- 431. Small Craft Advisory until 1 PM EDT this afternoon for ANZ450>455. && $$ SYNOPSIS...AKL/Gorse/Johnson NEAR TERM...Gorse SHORT TERM...AKL/Johnson LONG TERM...AKL/Gorse/Johnson AVIATION...Gorse/Johnson MARINE...Gorse/Johnson